Process for the production of sulfuric acid without chambers and towers



T. SCHMIEDEL AND H. KLENCKE. PROCESS FOR THE PRODUCTION OF suLFumc ACID WITHOUT CHAMBERS AND TOWERS.

APPLICATION HLED AUG. 13. I920.

Patented Dec. 6, 192L- 2 $HEET$-SHEET I.

Inveniurs:

M1 WM,mW.L-nEWI T. SCHMIEDEL AND H. KLENCKE.

PROCESS FOR THE PRODUCTION OF SULFURIC ACI D WITHOUT CHAMBERS AND TOWERS. APPLICATION FILED AUG.I3, 1920 1,399,526,. Patentell m 6, 1921.,

2 SHEETS-SHEET 2.

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HANS xnnncxn, or rumour- ON-THEMAIN, GERHANY, JASSI GNORS TO ED. GREUTERT & 01E, 0] BASED, SWIT- znnnann,

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.terstrasse 3, and Frankfort-on-the-Main,

Schwanthalerstrasse 72, respectively, have invented certain new and" useful Improvements in Processes for the Production of Sulfuric Acid Without Chambers and Towers,

\ for which I have filed applications in Germ many, Au 8, 1919; Austria, Oct. 16, 1919;

Sweden, 0v. 25, 1919; Norway, Nov. 25, 1919; Czechia, Dec. 20, 1919; France, Mar.

4, 1920; Italy, Mar. 27, 1920; England, Mar.

31,1920; Belgium, Apr.-2, 1920; Holland, pr. 9, 1920; Spain, Apr., 1920; Switzers land, Apr., 1920; Hungary, Apr., 1920,) of which the-followin is a specification,

This invention relates to a process for the production of sulfuric acid without chambers and towers.

The'production of sulfuric acid from gases containing sulfurous acid (roasting-furnace gases and the like) hasapart from the so called contact process-never been carried I out on a large scale without using lead chambers or towers. Although a number of proposals have already been made for the production of sulfuric acid without chambers and towers, these proposals have not led to any practical result, principally because with the proposed means no really intensive as liquid reaction could be obtained, since tor this purpose the gas containing sulfurous acid must be brou ht into intimate contact as quickly as possible, with a constantly re new-able exceedingly large quantity of finely divided nitrosyl acid. By an extremely large amount of nitrous ac1d is to be understood an amount so large that in contact with any S0 content occuring in the plant the power of the nitrosyl acid to oxidize S9, is maintained. unconditionally, therefore, there is no nitrosyl acid in the plant which is so weak as to be inactive. Furthermore it is necessary to keep the strength of the nitrosyl acid within certain limits, in order that on the one hand suficient water for quick reaction may be present in the acid Specification of Letters Patent. Application flled'A uguat 18,1920. serial No. 403,417.

atented DecJi, 1921.,

- and on the other hand the capacity of the acid to contain nitrous gases and to take up nitrous gases that have been liberated may.

nevertheless be preserved.

According to the present invention, the problem of producing sulfuric acid without 4 lead chambers and towers in an economical manner with proved success on a practical scale is solved by bringing into contact wlth the gases containing sulfurous acid, the

largest possible amount of nitrosyl acid of between 541 and 58 B. strength,and in an extremely fine state of subdivision, in a mixing chamber, preferably by means of mechanical devices of any construction. The gases after having traversed the mixing device may be advantageously conducted through a chamber of moderate dimensions irrigated with nitrosyl acid of the same composition as that in the mixing chamber. By this means, the nitrous gases set free during the reaction in the mixing chamber have an opportunity of again exerting an oxidizing action on sulfurous acid, and are absorbed in the irrigating chambers to be returned in a dissolved condition to the mixing chamber, so that the proportion of nitrous contents in the acid there remains practically unaltered.

One mixing chamber and one irrigation chamber alone or one mixin chamber form in themselves a working unit towhich further units of the same kind may be attached as required. The mixing and irrigation chambers may be arranged in any way, provided the mixing chambers in articular are the use of the customary lead chambers or reaction towers in which the 0 containing gases are brought into contact and into reactlon with nitrosyl sulfuric acid by the help of mechanical mixing devices. In all these processes, however, the SU -containing gases containing gases enter it, there is found denitrated sulfuric acid. Furthermore the ni-- trogen oxid content of the acid increases until at the point where the SO, content of the gases is approximately zero, it reaches its iighest value. Thereafter the nitrogen oxid content of the acid decreases again until the end of the plant, because there sulfuric acid free from nitrogen oxid is yielded.

In contrast to this in the present process, the plant at the beginning, in the middle, and at the end,that is, in all stages of the process is .provided with nitrosyl sulfuric acid of the same nitrogen oxid content and in such amounts. that everywhere in the plant nitrosyl acid capable of reacting is present and runs away. The nitrosyl acid running away from the individual mixing devices difl'ers somewhat in its nitrogen oxid content; it is collected and mixed and imme-' diately returned into the circuit. Onlyso much nitrosyl acid as about corresponds to' the daily production of the plant of sulfuric acid is drawn off and denitrated to form commercial acid. This denitration, however, does not belong to the carrying out of the reaction in the present process, but can take place separately, for example, in the Glover tower of a chamber system. Because in the present process in all parts of the plant where sulfuric acid formation takes place,'especially however in the first part where large amounts of SO, are still present, the nitrosyl acid is never denitrated to inactivity, there is obtained in combination with the fine subdivision of the nitrosyl acid a hastening of the oxidation of the S0 content of the gas hitherto never reached, and with it the practical possibility of producing sulfuric acid in relatively small mechanical mixing devices on a'large factory scale.

In order to clearly understand the invention, reference is made to the accompanying drawings which shows by way of example a plant consisting of several mixing and irrigation devices.

Figure 1 is an elevational view and Fig. 2 is a plan view of the plant.

a is the inlet pipe for the gases containing sulfurous acid, for instance, ordinary roasting-furnace gases from pyriticzinc blende and the like, or also pure or waste gases from 'tight receptacle which is filled about one half with a solution of nitrosyl acid in sulfuric' acid. Eachmix-ing chamber is provided with a roller p", p, etc.,of acid-proof material, rotatably mounted and just touching the acid with its periphery or dipping slightly therein. A driving pulley t to t, is mounted on the elongated spindle 8 to n of the roller. The nitrosyl acid is centrifuged in'the form of a fine spray into the s chamber over the roller by the rapid revoliition so that the gases passing therethrough come into intimate contact with said spray. Part of the gases are drawn into the nitrosyl by means 0f-the roller and issue behind said roller, to reunite with the gases passing over the roller. Above the mixing chamber e is a container f charged with filling material which is irrigated with acid through the inlet pipe n to n, which acid runs into the. mixing chamber 6'. The gases leaving the mixing chamber are thus forced to pass through the irrigating chamber f and thence through the communication pipes d into the next mixing chamber 6 with adjoining irrigation chamber 7, and so on as required. The mixing chambers and accessories are arranged in cascade form in such way that the acid flows by itself from the uppermost mixing chamber down the lowest, by way of the overflow pipes g, g, 9, etc., and the inlet funnels h, 72. it, etc., provision being made for keepin the acid at uniform level by suitably-ad ust1ng the overflows. The acid comes from the mixin chamber a into the acid circulation tankz' rom which it is raised by the pump Zinto a high level tank 1:. From this it flows partly through the pipe m into the uppermost mixing chamber andpartly through the ipe n to the several lIIl tion chambers. 11 amount of .nitrosyl aci corresponding to thedaily production is diverted from the mixing chamber e into the denitrating chamber b and from thence is conducted, in a denitrated condition, to the place of consumption.

The individual rollers in the mixing chambers are driven by the motor 0 by means of belting. Instead of arranging the several chambers and tanks in cascade form, they may also be arranged on the same level, In

The mixing chamber may be in desired amounts being added in order to maintain the nitrosyl acid constantly at the concentration in nitrosyl, the composition being always in a state of change through the absorption of the generated sulfuric acid and through the normal loss of oxids of nitrogen. Thefdrive of the rollers of the mixing chambers'is started so that the gas space above the rollersis filled with a.fine' nitrosyl spray.

As soon as gases containing sulfurous acid of any strength whatsoever, hot or cold, encounter the very fine spray of nitrosyl acid (of about 56 B. strength) in the first mixing chamber a very brlsk reaction is set up at'once between the two in consequence of 25 the exceedingly great opportunity afforded for contact. That part of the gases which is forced in an extremely fine state of division into the nitrosyl by the roller is entirely oxidized therein. I

The result of this action is that a considerable part (up to 50% of the sulfurous acid) is oxldized in the first mixing chamber and that a corresponding amount of nitrosyl gases enter the gas mixture. Inasmuch as the gas mixture was in contact with comparatively strong sulfuric acid its percentage of water has become toosmall for further oxidation to take place in the form of a normal gas reaction, and a tendency is set up for the formation of nitrosyl-sulfuric acid or the deposition of chamber crystals. This is prevented by the gas mixture being now wetted in the intermediate chamber connected to the mixing chamber, with nitrosyl of the same concentration as that of the mixing chamber whereby nitrosyl-sulfuric acid is dissolved and the reaction between gas and liquid is again rendered possible. At the same time the irrigating acid redissolves the nitrous gases liberated in the mixin chamber and returns them into the mixlng chamber so that its stock of. nitrosyl is essentially main-- tained.

Une mixing chamber and one irrigating chamber thus form'a complete aggregation v which, given a slow flow of gas, 1s adapted to carry out the acid-forming process by working up the S0 gases and recovering the nitrogen-oxygen compounds. Consequently it isnot always necessary to pass the acid in a single current against the gases but the mixing and irrigation chambers may be supplied in parallel with acid of uniform composition. Therefore, if delib required strength of56 B.'and at a suitable sired, the repeated circulation of acid,

hitherto essential in chamber and tower systems, may be dispensed with. The practical advantage. of this circumstance is that the quantity of acid and therefore of nitro syl supplied to the individual mixing chambers connected in arallel to the acid supply can, if desire ,"be varied at any time and independently for each. The gas mixture leaving the irrigation chamber is passed, if necessar through further mixing chambers alternatlng' with irrigation chambers until the content in sulfurous acid is almost completely exhausted. Since, in this 'method of working the content of nitrous gases in the gas mixture at any time corresponds only to the amount of sulfurous acid coming into action at a given point, both the sulfurous acid and the gaseous nitrosyl have disappeared from the final gases, at the end of the system. These gases can, therefore, immediately be discharged into the open air.

For the production of commercial acid, an amount of nitrosyl acid which corresponds to the daily production must be denitrated. This is efl'ected by setting up in front of the first mixing chamber a similarly constructed denitrating chamber into which prart of the nitrosyl acid is admitted and cm which the gas mixture is passed into the first mixing chamber proper, without passing through an irrigation chamber. The denitrated acid is drawn ofi' separately and stored.

Tn this way a large quantity of sulfuric acid can be produced in a small space and with a comparatively small consumption of nitric acid and power. Since the prime cost of the plant is small, extensive buildings such as chambers and towers, being dispensed with, a highly important improvement is constituted by the new process on this account as well.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to; be performed, we declare what we claim is:

1. A process for manufacturing sulfuric acid without the customary lead chambers or reaction towers, comp-rising the bringing to ether of a solution of nitrosyl sulfuric acid in sulfuric acidin very fine subdivision, and SU -containing gases with the help of one or more mechanicalmixing devices, the solution being used in an amount such that at no point in the plant does the solution, as a result of the denitration loseits power of oxidizing SU 2. The process for manufacturing sulfuric acid without the customa lead chambers or reaction towers comprising the brin g together of a solutionof nitrosyl sulfuric acid in sulfuric acid in a fine state of subdivision, and Sfl -containing gases, with the help of one or more mechanical mixing devices, the solution being used in an amount such that at no point in the plant does it lose its power to oxidize SO, as the result of denitration, and the bringing back into the circuit of the solution w ich is passmg out of the plant, while an amountof the I solution corresponding to the production of state of sub-division,-and SO -containing gases, with the mechanical help of one or more roller devices, the solution being used in sufficient uantity such that at no place in the plant does the solution lose its power to oxidize SO as a result of denitration, and the h back into the circuit through the plant of thesolution flowing away out of the plant, while" an amount of the solution corresponding approximately to the production of sulfuric acid is separated out andcompletely denitrated to form commercial acid.

4. The process for manufacture of sulfuric acid without the customary lead chamber or reaction towers comprising the bringing together of a solution of nitrosyl sulfuric acid in sulfuric acid in a fine state of subdivision, and sO -containing gases, with the help of one or more mechanical mixing devices, wherein the gas is conducted be hind each mixing device and through a space which is sprayed with the same solution, the solution being used in an amount such that at no place in the plant does the solution lose its power to oxidize SO as a result of the denitration and the returning of the solution flowing away out of the plant into circulation through the plant, while an amount of the. solution corres onding to the production of sulfuric acid is separated and completely denitrated into commercial acid.

'5. The process for manufacturing sulfuric acid without the customa lead chambers or reaction towers, com rising the brim ing together ofnitrosyl sul uric acid in sul uric acld a fine state of subdivision, and S0 containing gases, with the use of one or more roller devices wherein the gas is conducted behind each mixin device and throu h the solution being use in an amount suc that at no place in the plant does the solution, as a result of denitration, lose its power to oxidize S0 and the return of the solution flowing away out of the plant into circulation through the plant, while an amount of the solution approximately corresponding to the production of sulfuric acid is separated and completely denitrated to form commercial acid.

6. The process for the manufacture of sulfuric acid without the customary lead chambers or reaction towers, consisting in the bringing together of a solution of nitrosyl sulfuric acid in sulfuric acid in a fine state of sub-division with SO -containing gases with the use of one or more roller devices, wherein the gas is conducted behind each mixing device and through a box-like space, where it is sprayed with the same solution, the solution being used in an amount such that at no point in the plant does the solution lose its power to oxidize SO as a result of denitration, and the return of the solution flowing away out of the plant into circulation through the plant, while an amount of the solution approximately corresponding to the production of the sulfuric acid is separated and is completely denitrated in a de-nitrator, which is connected to the first mixing device, by the fresh SO,- containing gas to form commercial acid.

' In testimony whereof we afiix our signatures in presence of two witnesses.

THEODOR SCHMIEDEL. i HANS KLENCKE.

Witnesses ROBERT Enema, LUDVIG Sonmmrwnr. 

